Rectification device having a forward pn junction and a reverse schottky barrier formed in an epitaxial semiconductor layer formed over a semiconductor substrate

Abstract

Disclosed is a rectification device, a method for manufacturing the same and an ESD protection device. The rectification device comprises: a semiconductor substrate with a doping type of P-type; an epitaxial semiconductor layer with a doping type of N-type and located on the semiconductor substrate; a first doped region with a doping type of N-type and located in the epitaxial semiconductor layer; wherein the semiconductor substrate and the epitaxial semiconductor layer are respectively used as an anode and a cathode of the rectification device, and the rectification device further comprises a reverse Schottky barrier being formed in the cathode. According to the disclosure, a reverse Schottky barrier is formed to reduce the parasitic capacitance of the diode at high voltages, thereby increasing the response speed of the ESD protection device at high voltages.

1 - 18 . (canceled) 
     
     
         19 . A rectification device, comprising:
 a semiconductor substrate with a doping type of P-type;   an epitaxial semiconductor layer with a doping type of N-type and located on said semiconductor substrate;   a first doped region with a doping type of N-type and located in said epitaxial semiconductor layer;   wherein said semiconductor substrate and said epitaxial semiconductor layer are respectively used as an anode and a cathode of said rectification device, and said rectification device further comprises a reverse Schottky barrier being formed in said cathode,   wherein a forward diode for current rectification is formed by said semiconductor substrate and said epitaxial semiconductor layer.   
     
     
         20 . The rectification device according to  claim 19 , wherein doping concentration of said first doped region is larger than that of said epitaxial semiconductor layer. 
     
     
         21 . The rectification device according to  claim 19 , further comprising an anode metal which forms said reverse Schottky barrier with said epitaxial semiconductor layer, wherein said first doped region and said anode metal are electrically coupled to each other. 
     
     
         22 . The rectification device according to  claim 21 , wherein said first doped region and said anode metal are two adjacent strip structures. 
     
     
         23 . The rectification device according to  claim 21 , wherein said first doped region is a strip structure, and said anode metal is a ring-like structure surrounding said first doped region. 
     
     
         24 . The rectification device according to  claim 23 , wherein said strip structure comprises a plurality of strips electrically coupled via electrodes. 
     
     
         25 . The rectification device according to  claim 19 , further comprising:
 a first electrode insulated from said epitaxial semiconductor layer and electrically coupled to said first doped region; and   a second electrode electrically coupled to said semiconductor substrate.   
     
     
         26 . The rectification device according to  claim 19 , further comprising:
 an isolation structure which extends from a surface of said epitaxial semiconductor layer into said semiconductor substrate for defining an active region of said rectification device.   
     
     
         27 . The rectification device according to  claim 26 , wherein said isolation structure is a doped region of P-type or a trench isolation. 
     
     
         28 . The rectification device according to  claim 19 , wherein said rectification device is configured to provide a current path from said anode to said cathode, through said forward diode, and through said reverse Schottky barrier. 
     
     
         29 . The rectification device according to  claim 27 , wherein said reverse Schottky barrier in said cathode is formed in said active region. 
     
     
         30 . An ESD protection device, comprising:
 said rectification device according to  claim 19 ; and   a Zener diode,   wherein said first doped region of said rectification device is coupled to a cathode of said Zener diode.   
     
     
         31 . The ESD protection device according to  claim 30 , wherein said semiconductor substrate of said rectification device is coupled to an input-output terminal, and an anode of said Zener diode is coupled to ground. 
     
     
         32 . A method for manufacturing a rectification device, comprising:
 forming an epitaxial semiconductor layer on a semiconductor substrate, said semiconductor substrate and said epitaxial semiconductor layer are respectively of P-type and of N-type;   forming a first doped region in said epitaxial semiconductor layer, said first doped region is of N-type; and   forming a reverse Schottky barrier in said epitaxial semiconductor layer,   wherein said semiconductor substrate and said epitaxial semiconductor layer are respectively used as an anode and a cathode of said rectification device, and a forward diode for current rectification is formed by said semiconductor substrate and said epitaxial semiconductor layer.   
     
     
         33 . The method according to  claim 32 , after said step of forming an epitaxial semiconductor layer, further comprising:
 forming an isolation structure which extends from a surface of said epitaxial semiconductor layer into said semiconductor substrate for defining an active region of said rectification device.   
     
     
         34 . The method according to  claim 32 , wherein said step of forming a reverse Schottky barrier in said semiconductor substrate comprises:
 forming an anode metal on said epitaxial semiconductor layer.